Circuit breaker



Jan. 28, 1941. w, FRANK r 2,229,842

CIRCUIT BREAKER Filed Jan. 8, 1938 2 ShBBtS-Sht 1 INSULATION- 24 /2 Jan. 28, 1941.

W. H. FRANK ETAL CIRCUIT BREAKER Filed Jan. 8, 193a 5 2 IN VENT 0R3 c Goa/aw.

ATTORNEY.

Patented Jan. 28, 1941 UNITED STATES CIRCUIT BREAKER William H. Frank. Elwood T. Hats, and Lawrence E. Fisher, Detroit, Mich.

Application January 8, 1938, Serial No. 188,953

16 Claims.

This application relates to circuit breakers. Principal objects of the present invention are to provide a novel circuit breaker mechanism, details of which will be described upon reference 5 to the appended drawings. In these drawings,

Fig. 1 shows in elevation and in "on position a circuit breaker having the novel mechanism hereof; i

Fig. 2 is an end section on line 2-2 of Fig. 1;

Fig. 3 is an exploded view showing details the mechanism;

Fig. 4 shows the breaker in the oil'"'position:

Fig. 5 shows the breaker just after overload release and Just before the parts are reset automatically in off" position following such release;

Fig. 6 shows the casing per se in elevation;

Fig. 7 is a section on line l--'i oi Fig. 1.

A circuit breaker of the type under consideration generally comprises a spring actuated mechanism and a handle for providing manual actuation thereof. with the parts so arranged that the handle may be moved manually to cause the breaker mechanism to moveto and from "on" and off" positions with a snap action, to close and open the circuit, and with the parts also so arranged that on a circuit abnormality, such as overload, a circuit current responsive'overload release latch (a bimetal warping element) will warp and destroy a latched connection between parts of the mechanism so that the spring of the mechanism will automatically cause movement of the mechanism out of on or closed circuit position and into an intermediate position to open the circuit, all without requiring or causing movement of the handle. If nothing exists to prevent further movement of the parts, as is normally the case and as is intended to be the case, the mechanism and handle will not come to rest in the intermediate position, but the spring will cause further movement of the mechanism into the ofi" position and will also cause movement of the handle into such ofi position, thus automatically resetting the parts following overload release into an of! position.

This application discloses a novel form of mechanism which is about to be described.

Referring to the drawings, it will be observed that Figs. 1-7 show an open top casing in on whose interior surfaces are formed guide slots 50 H receiving guide lugs I! of a contact bar H, also known as a contact arm and as a contact operating arm, at an end of which is the movable contact 15. Projecting downwardly from the bar is an integrally formed tongue IE to which is secured a circuit current responsive overload release latch ll formed as a bimetal warping element. A flexible lead 28 connects the latch IT to a binding part I! to which a load conductor (not shown) is secured. Formed on the end of the contact bar i4 is a downwardly pro- Jecting his 20 which is disposed within a hole El of a cradle or supplementary bar 22 at whose end are lugs 28 disposed within slots 24 of the contact bar with clearance between the cradle and the latch ll being established by the provision of a large clearance slot 23 in the cradle. An end of the cradl passes through a hole it of a part 2? which is secured to the cradle, with the cradle insulated from such part by the provision of a suitable insulating liner in the hole 26.

Side slots til of the cradle receive lugs ti formed on a spring link 32 disposed wi hin a coiled spring 38 whose end is seated in a spring socket 35 formed in the closed bottom. of the casing It.

Disposed on the end of the contact bar adjacent the contact it-is an insulation shield 36 provided with a hole 31 through which projects the contact it and this shield functions as an arc quenching means operating on contact break between contact I5 and the stationary contact 88 formed on the terminal strap 39 connected by the screw Ml to the terminal connection clip ti engaging the line conductor 62 which is shown as a bus bar. A shield 43 01' insulation material is provided on the terminal strap 39 to cooperate with the shield 86 for are quenching purposes.

Passing through the opposite sides of the easing 10 and disposed slightly above the guide slots I I therein is an axle pin 50 which Journals a handle 5| formed with downwardlyproiecting side flanges 52 and downwardly projecting end flanges 53. Projecting downwardly from the upper surface of the handle 5i and within and spaced from the flanges -53 thereof is a downwardly projecting rib 54 whose lower edge engages the upper surface of the contact bar it, as shown best in Figs. 1 and 2. The sides of the casing l0 dispose themselves within the spaces 'between the rib I54 and the side flanges 52 of the handle.

The rib 55 contains a hole 56 for cooperation with a lug 58 formed from and projecting upwardly from the contact bar M for purposes later to be described.

The operation of the mechanism will now be outlined. Normally the parts are in the "on" or closed circuit position of Fig. 1. The spring 33 has its line of action to the right 01 the engagement of the rib 54 with the contact bar l4 and consequently tends to rotate the contact bar and cradle as a unit counterclockwise about the rib 54 as a pivot. Such tendency is inhibited by the engagement of the contact I5 on the bar I 4 with the fixed contact 38 and consequently a pressure contact is established at this point by the spring pressure. The handle is maintained at rest by the spring pressure whose line 01' action is such that it tends to rock the handle clockwise on its axle 50 and such tendency is inhibited by the engagement of the right hand part of the handle with the right hand part of the casing as shown in Fig. 1.

If the handle is caused to rock counterclockwise by pressure on its left end, the parts will move to the position of Fig. 4. Pressure on the left end of the handle will rock the handle counterclockwise and move the end of rib 54 to the right, across the line of action of the spring 33, first compressing and then releasing spring 33. Such spring will now tend to snap the unit comprising the bar l4 and the cradle 22 clockwise on rib 54 as a pivot. Such tendency will cause the unit to move to open circuit position and come to rest in such position by virtue of the engagement of the left end of the contact bar with a stop 51 formed on the interior of the casing and also by the engagement of the cradle 22 with a stop 58 also formed on the interior of the casing; the parts thus will be seen to be at rest and maintained at rest by the spring pressure in the position of Fig. 4; the handle will also be maintained in its open circuit position by such spring pressure, which tends at this time to rock the handle counterclockwise on its axl'e 50 andwhich tendency is inhibited by the engagement of the left end of the handle with the left end of the casing. In such handle movement, handle rib hole will pick up lug 53 for positive pull up on bar I4, if it be stuck at contacts l5-38.

To return the parts to the closed circuit position of Fig. 1 it is merely necessary to rock the handle clockwise by pressing down on its right end. The end of rib 54 will cross the line of action of spring 33 and the latter will thereupon snap the unit (I4--|122) counterclockwise on the end of rib 54 as a pivot to the closed circuit position of Fig. 1 with the unit and the handle being maintained at rest in such position by the spring pressure.

It will be understood at this time that when the parts are in the on position of Fig. 1 or in the oiP position of Fig. 4 or are moving to and from such positions, when caused so to do by manual movement of the handle, that at all times the contact bar I4, the bimetal element l1, and the cradle 22 are relatively immovable and move as a unit. Under such circumstances the lower edge of the bimetal element l1 will constantly be in engagement with the upper edge of the part 21 positioned on the cradle 22.

If an overload occurs, the bimetal latch heats and: warps with the result that such latch warps to the left (Fig. '7) and Off the upper edge of the part 21. This destroys the latch connection between the parts l4 and 22 and permits them to move relatively for the automatic release operation which will now be described.

When such warping of the bimetal element takes place and destroys the latch connection between the bar I4 (fixed to the bimetal element l1) and the cradle 22 and permits spring 33 to move the cradle independently of the bar and handle, spring 33 first moves cradle 22 upward until such cradle engages the stop lug 58. Thereupon the cradle, and with it the bar l4, move around stop 58 and rib 54 as pivots to open the circuit between contacts l5 and 38, until the left end of the bar i4 engages the casing stop 51. This eifectively opens the circuit and this action takes piece without the necessity of and without causing movement of the handle 5|. Consequently, even if the handle be held against rocking, the mechanism can move to open circuit position and consequently the breaker as a whole can properly be considered as havingthe trip free characteristic.

If the handle not be held, as is generally the case and as is intended to be the case, the parts do not come to rest in the condition of Fig. 5 but move further to the position of Fig. 4 because of the spring pressure of spring33. This pressure causes the handle to rock counterclockwise to the position of Fig. 4; in such movement the handle hole 55 in its rib 54 picks up the lug 56 of the bar l4 and such bar moves with the handle up to the position of Fig. 4 where the parts come to rest, it being observed that.generally by this time the thermal element I! has cooled and has reached its normal position, that of being above and in engagement with the upper edge of the part 21.

Now having described a breaker mechanism hereof, reference will be had to the claims which follow for a determination of the invention hereof.

We claim:

1. A circuit breaker mechanism comprising a contact bar, a supplementary bar, and a thermal latch, an overcenter spring bearing against the supplementary bar, and an overcenter handle operatively connected to the contact bar, the bars being generally parallel and longitudinally extending, the spring and handle being generally transverse of and separated by the unit comprising the two bars, these being connected to each other by the latch.

2. A circuit breaker mechanism comprising a contact bar; a supplementary bar, and a thermal latch, an overcenter spring bearing against the supplementary bar, and an overcenter handle operatively connected to the contact bar, the bars being generally parallel and longitudinally extending, the spring and handle being generally transverse of and separated by the unit comprising the two bars, these being connected to each other by a pivotal connection and by said latch.

3. In a circuit breaker, a contact bar and a supplementary bar, a stationary contact, the contact bar being pivotally connected to the supplementary bar near one end of the contact bar, a circuit responsive latch latching the contact bar and the supplementary bar at the other end of the contact bar, said latch when unreleased oausing the contact bar and supplementary bar to move together without relative movement and when released permitting the contact bar and supplementary bar to move relatively, the latch being supported on and by the contact bar, and a spring engaging the supplementary bar between the points where the contact bar is connected to the supplementary bar, and, when the parts are in one position, causing the contact bar to move against the stationary contact and towards latch held position with respect to the supplementary bar, and being operative to cause relative movement of the contact bar, the stationary contact, and the supplementary bar in the event of latch release.

4. In a circuit breaker, a contact bar and a supplementary bar, a stationary contact, the contact bar being pivotally connected to the supplementary bar near one end of the contact bar, a circuit responsive latch latching the contact her and the supplementary bar at the other end of the contact bar, said latch when unreleased holding the contact bar and supplementary bar against relative movement and when released permitting the contact bar and supplementary bar to move relatively. the latch being supported on and by the contact bar, and a spring engaging the supplementary bar between the points where the contact bar is connected to the supplementary bar, the parts being so arranged that when they are in one position, the spring causes the contact bar to move against the stationary contact and towards the latch held position with respect to the supplementary bar, with the spring being operative to cause relative movement of the contact bar, the stationary contact, and the supplementary bar in the event or latch release, the parts also being so arranged that movement of the contact bar manually, when it is latched to the supplementary bar, causes movement of the spring to produce a snap action movement of the contact her.

5. In a circuit breaker, a contact bar and a supplementary bar, a stationary contact, the contact bar being pivotally connected to the supplementary bar near one end oi! the contact bar, a circuit responsive latch latching the contact bar and the supplementary bar at the other end of the contact bar, said latch when unreleased causing the contact bar and supplementary bar to move together without relative movement and when released permitting the contact bar and supplementary bar to move relatively, the latch being supported on and by the contact bar, and a spring engaging the supplementary bar between the points where the contact bar is connected to the supplementary bar, and, when the parts are in one position, causing the contact bar to move against the stationary contact and towards latch held position with respect to the supplementary bar, and being operative to cause relative movement of the contact bar, the stationary contact, and the supplementary bar in the event of latch release, whereaiter the latch relatches the contact bar and supplementary bar relatively.

6. In a circuit breaker, a contact bar and a supplementary bar, a stationary contact, the contact bar being pivotally connected to the supplementary bar near one end of the contact bar,

a circuit responsive latch latching the contact bar and the supplementary bar at the other end oi the contact bar, said latch when unreleased causing the contact bar and supplementary bar to move together without relative movement and when released permitting the contact bar and supplementary bar to move relatively, the latch being supported on and by the contact bar, and a spring engaging the supplementary bar between the points where the' contact bar is connected to the supplementary bar, and, when the parts are in one position, causing the contact bar to move against the stationary contact and towards latch held position'with respect to the supplementary bar, and being operative to cause relative movement of the contact bar, the stationary contact, and the supplementary bar in biy mounted supplementary bar pivotally contheeevent oi latchrelease, the contact bar and the supplementary bar lying alongside one another, in an elongated unit, the breaker having nected to said contact bar and positioned to be interlocked to' the contact bar by the element when the latter is under normal circuit influence, or to be released thereby when the latter is under abnormal circuit influence, a spring acting directly on said supplementary bar, the contact bar being arranged to be moved manually, the contact bar, the element, and the supplementary bar comprising elongated members arranged so as to be generally alongside one another, and to move generally along with one another. together or relatively as the case may be, the spring and the manually engageable suri'ace or the contact bar being on opposite sides of the group comprising the contact bar. the element, and the supplementary bar.

8. A circuit breaker comprising a contact bar, a circuit condition responsive trip control element or latch having an inherent characteristic to move in response to circuit conditions, a movably mounted supplementary bar pivotally con nected to said contact bar and positioned to be interlocked to the contact bar by the element when the latter is under normal circuit influence, or to be released thereby when the latter is under abnormal circuit influence, a spring acting directly on said supplementary bar the contact bar being arranged to be moved manually, the com tact bar, the element, and the supplementary bar comprising elongated members arranged so as to be generally alongside one another, and to move generally along with one another, together or relatively as the case may be, the spring and the manually engageable surface 0! the contact bar being on opposite sides oi the group comprising the contact bar, the element, and the supplementary bar, the parts being so arranged that on the arising of a circuit abnormality, the element moves to release the supplementary bar from the contact bar, whereupon the spring moves the contact bar and supplementary bar relatively, after which the spring moves the parts so as,to create once more an interlocking relation between the contact bar and the supplementary bar.

9. A circuit breaker including a movable contact, a stationary contact, a movable contact operating arm, a handle, and a thermally responsive latch for said arm, the handle and movable contact being so connected that movement of the handle in one direction causes the movable contact to withdraw from the stationary contact, and movement of the handle in the opposite direction causes the movable contact to approach the stationary contact, and a single spring for pressing the movable contact against the stationary contact when the parts are in circuit closed position, and for biasing the movable contact away from the stationary contact when the arm is released by the latch. the spring being connected to the contact operating arm free and independently of the handle, through a supplementary bar alongside the contact operating arm and latched tact, a stationary contact, a movable contact operating arm, a handle, and a thermally responsive latch for said arm, the handle and movable contact being so connected that movement of the handle in one direction causes the movable contact to withdraw from the stationary contact, and movement of the handle in the opposite direction causes the movable contact to approach the stationary contact, and a single spring for pressing the movable contact against the stationary contact when the parts are in circult closed position, and for biasing the movable contact away from the stationary contact when the arm is released by the latch, and for producing snap movement of the movable contact fol lowing movement of the handle, the spring being connected to the contact operating arm free and independently of the handle, through a supplementary bar alongside the contact operating arm and latched thereto by the latch, with the handle directly and constantly engaging the contact operating arm which carries the latch.

11. A circuit breaker including a movable contact, a stationary contact, a movable contact operating arm, a handle, and a thermally responsive latch for said arm, the handle and movable contact being so connected that movement of the handle in one direction causes the movable contact to withdraw from the stationary contact, and movement 01' the handle in the opposite direction causes the movable contact to approach the stationary contact, and a single spring for pressing the movable contact against the stationary contact when the parts are in circuit closed position, and for biasing the movable contact away from the stationary contact when the arm is released by the latch, the spring being connected to the contact operating arm free and independently or the handle, through a supplementary bar alongside the contact operating arm and latched thereto by the latch, with the handle directly and constantly engaging the contact operating arm which carries the latch, the latch being formed as an extended part of the arm, the arm and latch together comprising a unit having no fixed pivotal mounting but mounted on and by the handle.

12. A circuit breaker including a movable contact, a stationary contact, a movable contact operating arm, a handle, and a thermally responsive latch for said arm, the handle and movable contact being so connected that movement 01. the handle in one direction causes the movable contact to withdraw'from the stationary contact, and movement of the handle in the opposite direction causes the moveable contact to approach the stationary contact, and a single spring for pressing the movable contact against the stationary contact when the parts are in circuit closed position, and for biasing the movable contact away from the stationary contact when the arm is released by the latch, and for producing snap movement of the movable contact following movement or the handle, the spring being connected to the contact operating arm free and independently of the handle, through a supplementary bar alongside the contact operating arm and latched thereto by the latch, with the handle directly and constantly engaging the contact operating arm which carries the latch, the handle being of the push-manipulation type and so constructed and the parts being so connected that snap movement of the contact operating arm, caused by the spring and initiated by movement of the handle, will not be restrained on normal manipulation of the handle.

13. In a circuit breaker, a circuit responsive releasable latch, a stationary contact, a contact bar and a supplemental bar, the bars being pivot- 5 ally interconnected near one end, and releasably interlatched relatively at the other end by said latch, the latch being supported on and by the contact bar, and a spring engaging the supplemental bar between the points where the bars are relatively interconnected, the parts being so arranged that when they are in one position, the spring biases the contact bar against the stationary contact and towards latch held position with respect to the supplemental bar, with the 115 spring being operative to bias the contact bar to move relative to the stationary contact and the supplemental bar in the event of latch release.

14. In a circuit breaker, a circuit responsive releasable latch, a stationary contact, a manually actuable contact bar and a supplemental bar, the bars being pivotally interconnected near one end, and releasably interlatched relatively at their other end by said latch, the latch being sup- 2:; ported on and by the contact bar, and a spring v engaging the supplemental bar between the points where the bars are relatively interconnected, the parts being so arranged that when they are in one position, the spring biases the 80 contact bar against the stationary contact and towards latch held position with respect to the supplemental bar with the spring being operative to bias the contact bar to move relative to the stationary contact and supplemental bar in the event of latch release, the parts also being so arranged that movement of the contact bar manually, when it is latched to the supplementary bar, causes movement of the spring to produce a snap action movement of the contact bar into its flnal resting places in circuit open and circuit closed positions.

15. A circuit breaker mechanism comprising a contact bar, a supplementary bar, and a thermal latch, an overcenter spring bearing against the supplementary bar, and an overcenter handle operatively connected to the contact bar, the bars being generally parallel and longitudinally extending, the spring and handle being generally transverse of and separated by the unit comprising the two bars, these being connected to each other by the latch, the latch being carried by one 0! the bars, and means for restraining undesired.- relative movement of the two bars comprising a lug on one of them at all times disposed in a hole in the other.

16. A circuit breaker mechanism comprising a contact bar, a supplementary bar, and a thermal latch, an overcenter spring bearing against the supplementary bar, and an overcenter handle operatively connected to the contact bar, the bars being generally parallel and longitudinally extending, the spring and handle being generally transverse of and separated by the unit comprising the two bars, these being connected to each other by a pivotal connection and by said latch, the latch being carried by one of the bars, and means for restraining undesired relative movement of the two bars comprising a lug on one of them at all times disposed in a hole in the other.

WILLIAM H. FRANK. ELWOOD T. PLATZ.

LAWRENCE E. FISHER. 1 

